


And I Know That You'll Love Me No Matter What

by smexyoikawa



Category: Haikyuu!!, The Mortal Instruments Series - Cassandra Clare
Genre: Alternate Universe - Shadowhunter Chronicles Fusion, Haikyuu!! AU Week
Language: English
Status: In-Progress
Published: 2017-02-17
Updated: 2017-12-06
Packaged: 2018-09-25 04:06:03
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 2,756
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9801938
Author URL: https://archiveofourown.org/users/smexyoikawa/pseuds/smexyoikawa
Summary: Iwaizumi Haijime is a shadowhunter sent to watch over a certain Oikawa Tooru.Oikawa Tooru is a mundane who has his eyes on a certain Iwaizumi Hajime.Things were about to take an interesting turn.In other words, a Mortal Instruments × Haikyuu AU that no one asked for





	1. Chapter 1

**Author's Note:**

> Ok so i love the mortal instruments series, you know shadowhunters and demon hunting and stuff, but i also happen to love haikyuu just as much. So i thought: why don't i combine the 2 of them hagaha so yeah

**Iwaizumi's POV:**

Iwaizumi never understood the Clave.

They were disorganised and heck, sometimes even Iwa himself felt like he could manage a council of shadowhunters better than the Clave did.

Despite his qualms about the Clave, he never questioned the Clave's doings (outloud) and simply complied. That, however was until he was assigned to protect a mundane (which sounded ridiculous to Iwa).  
  
"Who is this Oikawa Tooru and more importantly, why am I supposed to protect a mundane?" Iwaizumi asked even though it sounded more like a demand than a question.

Daichi shrugged. "Dunno, Clave's orders. Can't help it."

"But you are the Consul."

Daichi spun around, his gaze hardenning.

"Look, you and I both know that this wasn't just my decision alone. We held a referendum during the Council and they voted for you. And to answer your previous question, Oikawa Tooru is not just a mundane." Daichi paused for effect.

Iwaizumi looked on, waiting for Daichi to finish.

"He's something different," Daichi continued, "and that's why I want you to watch over him until he shows further signs of possessing angel blood."

As the Consul, the highest appointed official in the Clave, Daichi had a serious gaze with a 'no nonsense' attitude. But sometimes, Iwaizumi forgot that Daichi was human too and hid his true feelings behind this facade of his.

Iwaizumi studied Daichi.

His gaze was hard, though his eyes seemed to plead for Iwaizumi to understand.

Iwa understood.

"Alright," he says resigned, "I'll do it."

°°°  
Entering a portal made Iwa feel like air was being sucked out of his lungs and his entire being. It was so suffocating that Iwa was surprised to find himself alive and kicking when he tumbled out of the portal, gasping for air. Yes, portalling was that bad. For Iwa at least.

Relieved, Iwaizumi stands but then, he remembers that he also has motion sickness and that travelling through a portal was like gyrating through space and time. Iwaizumi lets out a low groan before proceeding to puke in the nearby bush. When he was done puking his guts out (it was his mom's good ol' mac n cheese and god, iwa loved those), Iwaizumi stood up to survey his surroundings. He was sure that he had just puked in someone's backyard and that they would sue him for trespassing. Does portalling into one's house count as trespassing anyway? Iwa hoped not.

At first sight, the house looked just like any other regular house around the neighbourhood. But after a while, Iwa realised that the house was glamoured heavily to blend in with its surroundings. Through its glamour, Iwa saw a meticulously manicured lawn which amused Iwa because it contrasted greatly with the well-worn chapel (that needed alot of maintenance) it was paired with.

Iwaizumi sauntered forward gingerly, his shadowhunter instincts kicking in. Sometimes, Iwa hated how he was such a softie, despite his looks. If he hadn't agreed to the Clave's instructions, he wouldn't have puked out his lunch. Moreover, Iwaizumi had no idea where he was and he was starting to wonder if the portal had actually portalled him to the wrong place.

Damn you, stupid portal.

And as if on cue, Iwaizumi stopped short infront of a pair of familiar gravel eyes. And there he was, the statue of the angel Raziel. Erected from the ground, a magnificent sight to behold. It then dawned upon him that this house belonged to a shadowhunter (and that the portal didn't bring him to the wrong place).

"Not so used to portalling huh", he heard a voice behind him. 

Iwaizumi turned, ready for a fight, only to find himself gawking at a young man dressed in nothing but his boxers. Iwaizumi tried not to stare at his bulge so he diverted his attention to his face. Boxers had dark hair and half-lidded eyes laid with judgement but the most prominent feature that stood was his brows. How does one have such thick eyebrows, Iwa ponders.

Boxers clears his throat.

"I'm sorry, did I disturb you or something", Iwaizumi says quickly, averting Boxer's gaze.

Boxers raises a brow and chuckles.

"Yes, and you should be terribly sorry for vomitting into my plants."

Oh shit. He knows. "I'm so sor-"

"MATTTTTSUUUUNNNNNN, I TOLD YOU NOT TO GO OUT IN JUST YOUR UNDERWEAR"

Another exasperated voice interupts Iwaizumi, cutting off his apology.

A man with light pink hair then emerges from within the chapel. He frowns, placing his hands firmly on his hips.

Where are his eyebrows, Iwa wonders for the second time today, his eyes darting back and forth between boxers dude- Mattsun and browless guy.

Maybe boxers should donate some brows to pinky.

"I didn't do it on purpose! Heard some noises in the backyard so I went to check it out." Mattsun defends himself, gesturing towards Iwaizumi.  
"Oh," pinky says, turning his attention to Iwaizumi, "you must be Iwaizumi-kun."

°°°  
"Okay, so you're a warlock," Iwaizumi points at Matsukawa, Mattsun for short who nods eagerly, "and you're a shadowhunter." Iwaizumi motions towards Hanamaki, the pink-haired guy who all but grins, holding up a peace sign.

"Yes, you are absolutely correct." Mattsun agrees. "And we need your help."

"Let me guess. Is it regarding a certain mundane," Iwaizumi deadpans.

Mattsun and Hanamaki don't respond, but their expressions were answer enough.

And so, that was how Iwaizumi got himself enrolled into a Seijoh High School, just so that he could help Mattsun and Maki monitor the mundie while they were rotting away in the Miyagi Institute.

Iwaizumi sighs, Hanamaki's words replaying in his mind. "I requested for more back-up because I couldn't monitor and manage the institute simultaneuosly. Besides, Mattsun isn't even a shadowhunter, he can only do so much."

Iwaizumi sighs again, reminded of his current predicament. How was Iwa going to find this Oikawa Tooru if he didn't even have a single clue of how he looked like?

"Why the grumpy face?", a voice snaps Iwaizumi out of his reverie.

"Huh." Iwa could only manage for he had not noticed someone sitting in front of him.

"It's okay, being the new kid always suck. I mean, you're the new kid in school right?" Iwaizumi looks up to meet a pair of chestnut brown eyes sparkling with curiosity. 

Iwaizumi nods, momentarily speechless.

"Then you're lucky, new kid! I'm Oikawa Tooru." the boy with gorgeous eyes grins, sticking out his hand.

"Iwaizumi Hajime." Iwa blurts, taking Oikawa's hand, offering him a small smile.

Well, that was easy.. Iwaizumi muses, his smile growing wider. 


	2. Chapter 2

**Summary for the Chapter:**

> A bunch of "oh yes!"s followed by an "oh no!"

**Notes for the Chapter:**

> I have no idea where this story is going but oh well

**Oikawa's POV:**

It was lunchtime when Oikawa first saw the new kid.

"I wonder who that dark hair cutie is." Oikawa mumbles to himself, thoughts running abok in his head. They ranged from "woah, he's hot-" to "is he in a gang" then to "i should go talk to him" and to "i think i'm in love".

Dressed in black from head to toe, the new kid looked like he was about to head to a funeral (probably Oikawa's). He had a perpectually irritated look plastered on his face too, which made him look intimidating and unapproachable. Not to mention the strange tattoos decorating his muscular arms (which Oikawa would totally hit on) that completed the look.

However, there was something about him- the way he carried himself that made Oikawa eager to know him. 

Taking a deep breath, Oikawa scooted over to the new kid. Placing his tray gracefully on the table, Oikawa took a seat directly infront of Iwa. Oikawa knew that it was creepy of him to do so, but he couldn't help it (though honestly he didn't care). 

Up close, the new kid looked even more attractive. His hair was a stark midnight black, his eyes dark brown, rimmed with a pair of strong arched brows.

Definitely Oikawa's type. 

If only he smiled, a small voice nags at Oikawa which he ignores. 

Instead, Oikawa continues staring into the new kid's face, mesmerized. It was starting to get a little weird yet the new kid didn't seem to notice, much less respond. 

Oikawa was getting tired of waiting.

"Why the grumpy face?" Oikawa asks, genuinely curious. 

"Huh." Shock and confusion flickers in the new kid's eyes and it seemed that he had just noticed Oikawa sitting in front of him.

But it didn't matter, Oikawa had his attention now. 

"It's okay, being the new kid always suck. I mean, you're the new kid in school right?" 

New kid nods. 

"Then you're lucky, new kid! I'm Oikawa Tooru." Oikawa grins, extending his right hand. Taking his hand, the new kid smiles. 

"Iwaizumi Hajime," came his gruff reply.

And sweet baby jesus, Oikawa thinks, he looks even better when he smiles. 

°°°

**Iwaizumi's POV:**

Later on, Oikawa offers to show Iwaizumi around the school compound which Iwaizumi gratefully accepts.

It didn't take long for Iwaizumi to figure out that it was wiser to have someone guide him than wander around alone. After all, mundane schools were big and were unfamiliar territory (note that Iwa has never set foot into a mundane school before and actually got lost trying to find the washroom). 

Oikawa gestures animatedly to a five-storey building on his right, "So this is the classroom block, where we have classes, of course."

"And this is the...", he continues, but Iwaizumi was barely listening.

Distracted by Oikawa's eyes, Iwaizumi's mouth parts slightly. His eyes were a warm chocolate brown, and they turned into million shades of gold as sunlight reflected off them.

Iwaizumi had never seen eyes so beautiful before and what did they say: the eyes are the window to the soul. 

"Iwa-chan..? Are you listening?" 

"What? Sorry, I was distracted." Iwaizumi blushes, running a hand through his hair. 

"It's okay, Iwa-chan. We can always- wait! You didn't protest when I called you Iwa-chan!" Oikawa gasps, "People always have violent objections when I call them -chan!" 

Iwaizumi lets out a laugh.

"Hmmm, I don't really care about all these honorifics, so you can just stick to whatever you want to call me." Iwa muses. 

"Yay!!!" Oikawa cheers and Iwaizumi couldn't help but compare him to a 7 year old child. The similarities were uncanny. 

"Say Iwa-chan, want to exchange phone numbers?" 

"For what?" Iwaizumi inquires, scratching his head.

At first, the notion of even having a cellphone was baffling to Iwa. Back in Idris, there was no reception or wifi of any sort so there was no need for a phone. But Daichi had insisted then, that Iwaizumi get a phone before he left for Miyagi, saying that it was for communication's sake (and self entertainment too).

Iwaizumi couldn't comprehend the reason behind it.

Nonetheless, he got a phone anyway, a pretty decent iPhone at that and left for Miyagi. 

It all made sense now...

"To talk more of course! We're friends aren't we?"

Iwaizumi's mouth twitches. 

"Sure, why not."

°°°

Iwaizumi returns to the Institute only to be greeted by his newly self-proclaimed dads. 

"How was first day of school, son." Hanamaki asks in a low gruff voice. Behind him, Matsukawa snickers.

"Oh, fuck off." Iwa mumbles under his breath. 

Hanamaki and Matsukawa both gasp in unison.

"How uncouth, Iwaizumi!" "Profanities! At such a young age!"

"This must be your doing, Issei!"

"No, you're the one who swears infront of our son all the time, Hiro."

"Don't talk to me or my son ever again."

"Dude, that meme is so outdated."

"Fine! Let's divorce!"

Iwaizumi rolls his eyes at their lovers' quarell and sends a silent prayer to God.

Just then, Iwa's phone rings. Of all times. 

"Oh? Pretty boi's got a call from someone?" Mattsun wiggles his brows. 

"On his first day of school!" Maki says exasperated. 

"Excuse me, I need to take this call." Iwaizumi mumbles, making his way out of the institute. 

"Be safe!!", he hears Maki before the door closes after him.

Iwaizumi rolls his eyes. If there was any part of his body that had the most exercise, it would be his eyes. 

"Moshi moshi?" Iwaizumi raises his phone to his ear without bothering to check its caller ID. There was only one person who would call him anyway. 

"I- iwa-chan? Are you there?" Iwazumi hears Oikawa's voice loud and clear, but there was something about his tone that alarmed Iwaizumi. 

"Yes, Oikawa, what is it?" Iwaizumi prods on. 

"Iwa-chan, I'm scared. Theres- theres someone at the door and I'm home alone. I checked, they were a bunch of _black clad men with weapons-_ I don't think they're cosplayers and-" 

Before Iwaizumi could respond, he hears a resounding crash from the other end, followed by an ear piercing scream. 

Then, the line cuts off. 


	3. Chapter 3

**Notes for the Chapter:**

> I am so so sorry for disappearing. I just couldn’t find any motivation to write and I didn’t have any inspiration. But- heres a new chapter that I pulled together a few days ago. I hope its not too bad!

**Oikawa’s POV:**

Given the situation, Oikawa's natural instinct was to run. Oikawa was good at running, in fact he loved it.

But he couldn't.

Not when he was scared stiff, his legs rooted to the asphalt. I mean who wouldn’t be?

The black clad men he saw outside swarmed into Oikawa's house, having broken down his front door. They surrounded Oikawa in an instant, preventing his escape. Oikawa wondered how the police were not notified of this yet. His neighbour, Sugawara was always poking around his house, giving him cookies and you know- just neighbour stuff. He prayed that Suga noticed the bunch of hooligans outside his door and called the police.

"W-who are y-you" Oikawa could only manage.

One of the black clad men approaches Oikawa, unsheathing a knife from his belt.

“Move and I’ll slit your throat” he growls, holding the knife to Oikawa’s throat.

The cold tip of the blade pressed into Oikawa’s skin and Oikawa suppresses a shiver.

“Now, now, don’t scare the poor thing.” A low and monotonous voice speaks. 

From Oikawa’s peripheral vision, he sees the black clad men break their ranks, and allow a big man with broad, thick shoulders through. He strides in, taking large steps.

“Besides, we have orders not to harm him.”

The man, who had his knife to Oikawa’s throat bows his head and lowers his arm.

“Good.” man with broad shoulders nods in approval.

He turns to face Oikawa and clears his throat.

“Pardon the intrusion. I am Ushijima Wakatoshi and these are my.. would you say subordinates? My master would like to see you and we would appreciate it if you could cooperate with us. Of course.. if you resist, things will get a little nasty.” He says with a small smile.

“But didn’t you say that you have orders not to harm me.” Oikawa squeaks. 

Ushijima laughs. 

“My, my, you’re a smart one. I like you already. But to answer your question, that is provided you do not try anything funny.”

Oikawa inhales sharply. He was giving Oikawa no choice at all.

“Fine, I’ll come with you.”

***

**Iwaizumi’s POV:**

Iwaizumi tried to call Oikawa several times but his phone rang on through.

_This user is currently unavailable. Please try again later._

“Damn it!”, Iwaizumi cursed.

He’d messed up on the first day of his job.

Of all things, was it so hard to protect a human?

“What happened?” Hanamaki peers into Iwa’s phone.

“It’s the mundie, isn’t it?” Matsukawa pipes in, with a seemingly worried frown.

“He said some black clad men were outside his door.. I’m guessin-“

“Shadowhunters.” Hanamaki hisses.

“Shit.” Matsukawa mumbles to himself. “Could it be Ushijima?“

“That bitch!” Hanamaki snaps.

Iwaizumi groans. Ushijima was trouble.

You see, Ushijima _used_ to be a shadowhunter. What’s more is that he used to be Iwaizumi’s _parabatai_ too. That though, was until he decided to betray the Clave and serve another master- the fallen angel, Lucifer.

Iwa knew Ushijima inside out. After all, they were childhood friends and _parabatai_.

Iwaizumi knew that once Ushijima sets his mind on something, he won’t rest until he gets what he wants.

But what did he want with Oikawa, a _mundane_?

After spending some time with Oikawa, Iwaizumi concluded that Oikawa was just a normal human. Thats right, no signs of shadowhunter blood. He didn’t even have the sight or even believed in fairies and werewolves.

“Hey, do you believe in fairies and all?” Iwaizumi had asked casually.

“Fairies? Of course not! Aliens are the real deal.” Oikawa said, looking at Iwa as if he were dumb, before blabbering about the recent UFO sightings and his own theories about aliens.

Iwa did not understand a single thing Oikawa was saying but found it kind of cute.

The thought of Oikawa made Iwaizumi’s heart skip a beat.

Just wait for me, Oikawa. I’m coming to get you.

**Notes for the Chapter:**

> In case y’all were wondering:  
> Parabatai are Shadowhunters who have taken an oath in front of the Council to fight together as lifelong partners. A Shadowhunter may choose only one parabatai in their lifetime and cannot perform the ritual more than once. Like the marriage bond, the parabatai nond is broken only by the death of one of the members of the partnership.


End file.
